Vehicular lamp with LED light source having uniform brightness

• US 6,637,923 B2
• Filed: 08/06/2002
• Issued: 10/28/2003
• Est. Priority Date: 08/15/2001
• Status: Expired due to Fees

• Current Assignee: Koito Manufacturing Company Limited
• Original Assignee: Koito Manufacturing Company Limited
• Inventors: Amano, Yasuyuki
• Primary Examiner(s): Tso, Laura K.
• Application Number:
  US10/212,038
• Publication Number:
  US 20030035298A1
• Time in Patent Office: 448 Days
• Field of Search: 362/545, 362/544, 362/543, 362/542, 362/541, 362/540, 362/241, 362/245, 362/297, 362/346, 362/800
• US Class Current: 362/545
• CPC Class Codes: B60Q 1/2607 comprising at least two indicating lamps
• CPC Class Codes: B60Q 1/2696 Mounting of devices using LEDs
• CPC Class Codes: F21S 43/14 Light emitting diodes [LED]
• CPC Class Codes: F21S 43/26 Refractors, transparent cover plates, light guides or filters not provided in groups F21S43/235 - F21S43/255
• CPC Class Codes: F21S 43/30 characterised by reflectors
• CPC Class Codes: F21S 43/40 characterised by the combination of reflectors and refractors
• CPC Class Codes: F21V 5/045 the lens having discontinuous faces, e.g. Fresnel lenses

Abstract

A vehicular lamp which irradiates a light by means of indirect illumination employing an LED light source and having an improved appearance when the lamp is lit. Light from an LED light source is formed into an upward parallel light flux by a Fresnel lens and reflected toward the front of a lamp by a reflector. The reflecting surface of the reflector is formed in a stepped shape by providing a reflective element and a step portion in each of a plurality of segments which are sectioned at a uniform interval in a vertical direction. The width in the longitudinal direction of the lamp of each of the reflective elements is gradually increased as the distance of the reflective elements increases from the intersection of the central axis of the parallel light flux and the reflecting surface. Accordingly, the incident light flux is made substantially constant among all the reflective elements, and hence the brightness of the light emitted by the lamp is made uniform.

Claims

1. A vehicular lamp comprising:

an LED light source;

a lens for forming light from said LED light source into a parallel light flux;

a reflector for reflecting the parallel light flux toward a front of said lamp; and

a translucent cover provided on a front of said reflector, a reflecting surface of said reflector being sectioned into a plurality of segments at a substantially uniform interval with respect to a radiating direction of said parallel light flux, and a reflective element and a step portion being formed in each of said segments whereby said reflecting surface is formed in a stepped shape, and a width in a longitudinal direction of said lamp of said reflective elements in peripheral areas on both sides in said radiating direction of said parallel light flux of a central area near an intersection point with respect to a central axis of said parallel light flux on said reflecting surface being greater than said reflective elements in said central area.

2. The vehicular lamp according to claim 1, wherein said width in said longitudinal direction of said lamp of said reflective elements increases on both sides in said radiating direction of said parallel light flux in accordance with distance from said intersection point between said parallel light flux and said central axis.

3. The vehicular lamp according to claim 2, wherein said width in said longitudinal direction of said lamp of each of said reflective elements is such that incident light fluxes onto all said reflective elements are substantially equal to each other.

4. The vehicular lamp according to claim 1, wherein each of said reflective elements comprises a curved surface which reflects said parallel light flux in a diffused manner in a vertical direction and a lateral direction.

5. The vehicular lamp according to claim 1, wherein said lens comprises a Fresnel lens comprising a plurality of Fresnel lens elements formed on a surface of said Fresnel lens on a side of said LED light source, and a plurality of deflection lens elements for radiating said parallel light flux in a direction inclined at a predetermined angle with respect to an optical axis of said Fresnel lens formed on a surface of the Fresnel lens on a side of said reflector.

6. The vehicular lamp according to claim 1, further comprising a second lamp unit provided in front of said LED light source and said lens.

7. A vehicular lamp comprising:

an LED light source;

a Fresnel lens for forming light from said LED light source into a parallel light flux;

a reflector for reflecting the parallel light flux toward a front of said lamp; and

a plain translucent cover provided on a front of said reflector, a reflecting surface of said reflector being sectioned into a plurality of segments at a substantially uniform interval with respect to a radiating direction of said parallel light flux, and a reflective element and a step portion being formed in each of said segments whereby said reflecting surface is formed in a stepped shape, each of said reflective elements comprising a curved surface which reflects said parallel light flux in a diffused manner in a vertical direction and a lateral direction, and a width in a longitudinal direction of said lamp of said reflective elements in peripheral areas on both sides in said radiating direction of said parallel light flux of a central area near an intersection point with respect to a central axis of said parallel light flux on said reflecting surface increases in accordance with distance from said intersection point between said parallel light flux and said central axis than said reflective elements in said central area.

8. The vehicular lamp according to claim 7, wherein said width in said longitudinal direction of said lamp of each of said reflective elements is such that incident light fluxes onto all said reflective elements are substantially equal to each other.

9. The vehicular lamp according to claim 7, further comprising a second lamp unit provided in front of said LED light source and said lens.

10. A vehicular lamp comprising:

an LED light source;

a Fresnel lens for forming light from said LED light source into a parallel light flux;

a reflector for reflecting the parallel light flux toward a front of said lamp; and

a translucent cover provided on a front of said reflector, a reflecting surface of said reflector being sectioned into a plurality of segments at a substantially uniform interval with respect to a radiating direction of said parallel light flux, and a reflective element and a step portion being formed in each of said segments whereby said reflecting surface is formed in a stepped shape, each of said reflective elements comprising a flat plane which reflects said parallel light flux toward said translucent cover, said cover comprising a plurality of diffusion lens elements, and a width in a longitudinal direction of said lamp of said reflective elements in peripheral areas on both sides in said radiating direction of said parallel light flux of a central area near an intersection point with respect to a central axis of said parallel light flux on said reflecting surface increases in accordance with distance from said intersection point between said parallel light flux and said central axis than said reflective elements in said central area.

11. The vehicular lamp according to claim 10, wherein said width in said longitudinal direction of said lamp of each of said reflective elements is such that incident light fluxes onto all said reflective elements are substantially equal to each other.

12. The vehicular lamp according to claim 10, further comprising a second lamp unit provided in front of said LED light source and said lens.

13. A vehicular lamp comprising:

an LED light source;

a Fresnel lens for forming light from said LED light source into a parallel light flux;

a reflector for reflecting the parallel light flux toward a front of said lamp; and

a translucent cover provided on a front of said reflector, a reflecting surface of said reflector being sectioned into a plurality of segments at a substantially uniform interval with respect to a radiating direction of said parallel light flux, and a reflective element and a step portion being formed in each of said segments whereby said reflecting surface is formed in a stepped shape, each of said reflective elements comprising a curved surface which reflects said parallel light flux in a diffused manner in one of a vertical direction and a lateral direction, said cover comprising a plurality of diffusion lens elements, and a width in a longitudinal direction of said lamp of said reflective elements in peripheral areas on both sides in said radiating direction of said parallel light flux of a central area near an intersection point with respect to a central axis of said parallel light flux on said reflecting surface increases in accordance with distance from said intersection point between said parallel light flux and said central axis than said reflective elements in said central area.

14. The vehicular lamp according to claim 13, wherein said width in said longitudinal direction of said lamp of each of said reflective elements is such that incident light fluxes onto all said reflective elements are substantially equal to each other.

15. The vehicular lamp according to claim 13, further comprising a second lamp unit provided in front of said LED light source and said lens.